Method op coating metals with mercury



UNITED STATES PATENT OFFICE.

JAMES P. A. MoCOY, 0F WILKINSIBURG, PENNSYLVANIA, ASSIGN'OR 17o WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA.

. METHOD OF COATING METALS WITH MERCURY.

No Drawing.

object to provide a method of causing mer-' cury to adhere to other metals with which it ordinarily has no afiinity.

Certain metals, such as iron and steel, have little or no surface attraction for mercu and, consequently, it is diflicult to wet the surfaces of such metals with mercury except by plating methods. It is, however, somet1mes very desirable to produce such an intimate contact between mercury and iron or steel, and my invention is directed to methods for effecting this result.

According to my present invention, I apply the mercury to the surface to be coated in the form of an amalgam'of tin or other metal with which mercury easily amalga-- mates. In one modification of my method, I use sufiicient mercury to give the amalgam a semi-liquid consistency, and this semia liquid amalgam is then rubbed over the surface of the metal to be coated, to which it readily adheres, the mercury in its amalgamated condition not being able to form itself into globules and run olf from the surface of the metal, as is the case when mercury alone is applied to iron or steel. The iron, steel or other metal to be coated should preferably be slightly heated before the application of the amalgam.

hydrochloric acid is next poured over the coated metal to perform the double function of cleaning themetal and of setting up a galvanic action which results in the depos1- the metal. The hydrochloric acid also dissolves a portion of the tin. The excess of tin' and mercury is then wiped off, and the surface of the iron or other metal is found to be thoroughly coated with mercury. This coating contains only a trace of the tin, and

the mercury coating appears not to be Specification of Letters Patent.

A suitable acid, such as hot, concentrated.

Patented Dec. 16, 1919.

Application filed April 12,1915. Serial No. 20,751.

of a piece of tin, thereby forming a surface A amalgam upon the tin. I then heat slightly the coated tin and also the iron or other metal to be cdated and place the amalgamated surface of the tin, wet with a little concentrated hydrochloric acid in contact with the iron. The coated side of the tin is then rubbed upon the iron, conveniently with cotton waste, and the surface of the iron becomes, coated with mercury, presumably through galvanic deposition. The tin is then removed, and all acid removed by washing, leaving a coating of almost pure mercury adhering to the iron.

The foregoing process is particularly use-- ful in the preparation of mercury seals for use in vapor electric apparatus such as mercury-vapor rectifiers, in which it is necessary to wet with mercury either an iron or steel container or a porcelain container, the

,surface of which is coated with a film or silver'or other metal. When porcelain is coated with silver, as is customary in constructing certain types of mercury-vapor apparatus, it is found that the silver coating cannot be amalgamated with mercury by ordinary means. By my method, however, mercury coatings may readily be applied to metal-coated porcelain.

My invention may be applied to many uses other than those specifically set forth and any metal may be used for making the preliminary amalgam which Will unite. with mercury to form plastic amalgams. It is to be understood that my invention comprehends all such modifications and adaptations als fall-within the scope of the appended c alms. v

*1 I claim as my invention: I tion of the mercury upon the clean surface of mates with mercury and transferring the mercury from the said metal to the surface to'be coated.

2. A process of coating metallic and metal-coated surfaces With mercury that the surface to be coated, and removing the comprises coating the surface of a plece of tin and the acid.

tin with mercury and transferring the mer- In testimony whereof I have hereunto 10 I cury from the tin to the surface to be coated vsubscribed my name this 30th day of March by placing the coated surface of the tin, Wet 1915.

with hydrochloric acid, upon the surface to be coated, rubbing together the tin and JAMES P. A. MOCQY. 

